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  <span class="target" id="manual:cmake-compile-features(7)"></span><section id="cmake-compile-features-7">
<h1><a class="toc-backref" href="#id3" role="doc-backlink">cmake-compile-features(7)</a><a class="headerlink" href="#cmake-compile-features-7" title="Link to this heading">¶</a></h1>
<nav class="contents" id="contents">
<p class="topic-title">Contents</p>
<ul class="simple">
<li><p><a class="reference internal" href="#cmake-compile-features-7" id="id3">cmake-compile-features(7)</a></p>
<ul>
<li><p><a class="reference internal" href="#introduction" id="id4">Introduction</a></p></li>
<li><p><a class="reference internal" href="#compile-feature-requirements" id="id5">Compile Feature Requirements</a></p>
<ul>
<li><p><a class="reference internal" href="#requiring-language-standards" id="id6">Requiring Language Standards</a></p></li>
<li><p><a class="reference internal" href="#availability-of-compiler-extensions" id="id7">Availability of Compiler Extensions</a></p></li>
</ul>
</li>
<li><p><a class="reference internal" href="#optional-compile-features" id="id8">Optional Compile Features</a></p></li>
<li><p><a class="reference internal" href="#conditional-compilation-options" id="id9">Conditional Compilation Options</a></p></li>
<li><p><a class="reference internal" href="#supported-compilers" id="id10">Supported Compilers</a></p></li>
<li><p><a class="reference internal" href="#language-standard-flags" id="id11">Language Standard Flags</a></p></li>
</ul>
</li>
</ul>
</nav>
<section id="introduction">
<h2><a class="toc-backref" href="#id4" role="doc-backlink">Introduction</a><a class="headerlink" href="#introduction" title="Link to this heading">¶</a></h2>
<p>Project source code may depend on, or be conditional on, the availability
of certain features of the compiler.  There are three use-cases which arise:
<a class="reference internal" href="#compile-feature-requirements">Compile Feature Requirements</a>, <a class="reference internal" href="#optional-compile-features">Optional Compile Features</a>
and <a class="reference internal" href="#conditional-compilation-options">Conditional Compilation Options</a>.</p>
<p>While features are typically specified in programming language standards,
CMake provides a primary user interface based on granular handling of
the features, not the language standard that introduced the feature.</p>
<p>The <span class="target" id="index-0-prop_gbl:CMAKE_C_KNOWN_FEATURES"></span><a class="reference internal" href="../prop_gbl/CMAKE_C_KNOWN_FEATURES.html#prop_gbl:CMAKE_C_KNOWN_FEATURES" title="CMAKE_C_KNOWN_FEATURES"><code class="xref cmake cmake-prop_gbl docutils literal notranslate"><span class="pre">CMAKE_C_KNOWN_FEATURES</span></code></a>, <span class="target" id="index-0-prop_gbl:CMAKE_CUDA_KNOWN_FEATURES"></span><a class="reference internal" href="../prop_gbl/CMAKE_CUDA_KNOWN_FEATURES.html#prop_gbl:CMAKE_CUDA_KNOWN_FEATURES" title="CMAKE_CUDA_KNOWN_FEATURES"><code class="xref cmake cmake-prop_gbl docutils literal notranslate"><span class="pre">CMAKE_CUDA_KNOWN_FEATURES</span></code></a>,
and <span class="target" id="index-0-prop_gbl:CMAKE_CXX_KNOWN_FEATURES"></span><a class="reference internal" href="../prop_gbl/CMAKE_CXX_KNOWN_FEATURES.html#prop_gbl:CMAKE_CXX_KNOWN_FEATURES" title="CMAKE_CXX_KNOWN_FEATURES"><code class="xref cmake cmake-prop_gbl docutils literal notranslate"><span class="pre">CMAKE_CXX_KNOWN_FEATURES</span></code></a> global properties contain all the
features known to CMake, regardless of compiler support for the feature.
The <span class="target" id="index-0-variable:CMAKE_C_COMPILE_FEATURES"></span><a class="reference internal" href="../variable/CMAKE_C_COMPILE_FEATURES.html#variable:CMAKE_C_COMPILE_FEATURES" title="CMAKE_C_COMPILE_FEATURES"><code class="xref cmake cmake-variable docutils literal notranslate"><span class="pre">CMAKE_C_COMPILE_FEATURES</span></code></a>, <span class="target" id="index-0-variable:CMAKE_CUDA_COMPILE_FEATURES"></span><a class="reference internal" href="../variable/CMAKE_CUDA_COMPILE_FEATURES.html#variable:CMAKE_CUDA_COMPILE_FEATURES" title="CMAKE_CUDA_COMPILE_FEATURES"><code class="xref cmake cmake-variable docutils literal notranslate"><span class="pre">CMAKE_CUDA_COMPILE_FEATURES</span></code></a>
, and <span class="target" id="index-0-variable:CMAKE_CXX_COMPILE_FEATURES"></span><a class="reference internal" href="../variable/CMAKE_CXX_COMPILE_FEATURES.html#variable:CMAKE_CXX_COMPILE_FEATURES" title="CMAKE_CXX_COMPILE_FEATURES"><code class="xref cmake cmake-variable docutils literal notranslate"><span class="pre">CMAKE_CXX_COMPILE_FEATURES</span></code></a> variables contain all features
CMake knows are known to the compiler, regardless of language standard
or compile flags needed to use them.</p>
<p>Features known to CMake are named mostly following the same convention
as the Clang feature test macros.  There are some exceptions, such as
CMake using <code class="docutils literal notranslate"><span class="pre">cxx_final</span></code> and <code class="docutils literal notranslate"><span class="pre">cxx_override</span></code> instead of the single
<code class="docutils literal notranslate"><span class="pre">cxx_override_control</span></code> used by Clang.</p>
<p>Note that there are no separate compile features properties or variables for
the <code class="docutils literal notranslate"><span class="pre">OBJC</span></code> or <code class="docutils literal notranslate"><span class="pre">OBJCXX</span></code> languages.  These are based off <code class="docutils literal notranslate"><span class="pre">C</span></code> or <code class="docutils literal notranslate"><span class="pre">C++</span></code>
respectively, so the properties and variables for their corresponding base
language should be used instead.</p>
</section>
<section id="compile-feature-requirements">
<h2><a class="toc-backref" href="#id5" role="doc-backlink">Compile Feature Requirements</a><a class="headerlink" href="#compile-feature-requirements" title="Link to this heading">¶</a></h2>
<p>Compile feature requirements may be specified with the
<span class="target" id="index-0-command:target_compile_features"></span><a class="reference internal" href="../command/target_compile_features.html#command:target_compile_features" title="target_compile_features"><code class="xref cmake cmake-command docutils literal notranslate"><span class="pre">target_compile_features()</span></code></a> command.  For example, if a target must
be compiled with compiler support for the
<span class="target" id="index-1-prop_gbl:CMAKE_CXX_KNOWN_FEATURES"></span><a class="reference internal" href="../prop_gbl/CMAKE_CXX_KNOWN_FEATURES.html#prop_gbl:CMAKE_CXX_KNOWN_FEATURES" title="CMAKE_CXX_KNOWN_FEATURES"><code class="xref cmake cmake-prop_gbl docutils literal notranslate"><span class="pre">cxx_constexpr</span></code></a> feature:</p>
<div class="highlight-cmake notranslate"><div class="highlight"><pre><span></span><span class="nf">add_library(</span><span class="nb">mylib</span><span class="w"> </span><span class="nb">requires_constexpr.cpp</span><span class="nf">)</span>
<span class="nf">target_compile_features(</span><span class="nb">mylib</span><span class="w"> </span><span class="no">PRIVATE</span><span class="w"> </span><span class="nb">cxx_constexpr</span><span class="nf">)</span>
</pre></div>
</div>
<p>In processing the requirement for the <code class="docutils literal notranslate"><span class="pre">cxx_constexpr</span></code> feature,
<span class="target" id="index-0-manual:cmake(1)"></span><a class="reference internal" href="cmake.1.html#manual:cmake(1)" title="cmake(1)"><code class="xref cmake cmake-manual docutils literal notranslate"><span class="pre">cmake(1)</span></code></a> will ensure that the in-use C++ compiler is capable
of the feature, and will add any necessary flags such as <code class="docutils literal notranslate"><span class="pre">-std=gnu++11</span></code>
to the compile lines of C++ files in the <code class="docutils literal notranslate"><span class="pre">mylib</span></code> target.  A
<code class="docutils literal notranslate"><span class="pre">FATAL_ERROR</span></code> is issued if the compiler is not capable of the
feature.</p>
<p>The exact compile flags and language standard are deliberately not part
of the user interface for this use-case.  CMake will compute the
appropriate compile flags to use by considering the features specified
for each target.</p>
<p>Such compile flags are added even if the compiler supports the
particular feature without the flag. For example, the GNU compiler
supports variadic templates (with a warning) even if <code class="docutils literal notranslate"><span class="pre">-std=gnu++98</span></code> is
used.  CMake adds the <code class="docutils literal notranslate"><span class="pre">-std=gnu++11</span></code> flag if <code class="docutils literal notranslate"><span class="pre">cxx_variadic_templates</span></code>
is specified as a requirement.</p>
<p>In the above example, <code class="docutils literal notranslate"><span class="pre">mylib</span></code> requires <code class="docutils literal notranslate"><span class="pre">cxx_constexpr</span></code> when it
is built itself, but consumers of <code class="docutils literal notranslate"><span class="pre">mylib</span></code> are not required to use a
compiler which supports <code class="docutils literal notranslate"><span class="pre">cxx_constexpr</span></code>.  If the interface of
<code class="docutils literal notranslate"><span class="pre">mylib</span></code> does require the <code class="docutils literal notranslate"><span class="pre">cxx_constexpr</span></code> feature (or any other
known feature), that may be specified with the <code class="docutils literal notranslate"><span class="pre">PUBLIC</span></code> or
<code class="docutils literal notranslate"><span class="pre">INTERFACE</span></code> signatures of <span class="target" id="index-1-command:target_compile_features"></span><a class="reference internal" href="../command/target_compile_features.html#command:target_compile_features" title="target_compile_features"><code class="xref cmake cmake-command docutils literal notranslate"><span class="pre">target_compile_features()</span></code></a>:</p>
<div class="highlight-cmake notranslate"><div class="highlight"><pre><span></span><span class="nf">add_library(</span><span class="nb">mylib</span><span class="w"> </span><span class="nb">requires_constexpr.cpp</span><span class="nf">)</span>
<span class="c"># cxx_constexpr is a usage-requirement</span>
<span class="nf">target_compile_features(</span><span class="nb">mylib</span><span class="w"> </span><span class="no">PUBLIC</span><span class="w"> </span><span class="nb">cxx_constexpr</span><span class="nf">)</span>

<span class="c"># main.cpp will be compiled with -std=gnu++11 on GNU for cxx_constexpr.</span>
<span class="nf">add_executable(</span><span class="nb">myexe</span><span class="w"> </span><span class="nb">main.cpp</span><span class="nf">)</span>
<span class="nf">target_link_libraries(</span><span class="nb">myexe</span><span class="w"> </span><span class="nb">mylib</span><span class="nf">)</span>
</pre></div>
</div>
<p>Feature requirements are evaluated transitively by consuming the link
implementation.  See <span class="target" id="index-0-manual:cmake-buildsystem(7)"></span><a class="reference internal" href="cmake-buildsystem.7.html#manual:cmake-buildsystem(7)" title="cmake-buildsystem(7)"><code class="xref cmake cmake-manual docutils literal notranslate"><span class="pre">cmake-buildsystem(7)</span></code></a> for more on
transitive behavior of build properties and usage requirements.</p>
<section id="requiring-language-standards">
<span id="id1"></span><h3><a class="toc-backref" href="#id6" role="doc-backlink">Requiring Language Standards</a><a class="headerlink" href="#requiring-language-standards" title="Link to this heading">¶</a></h3>
<p>In projects that use a large number of commonly available features from
a particular language standard (e.g. C++ 11) one may specify a
meta-feature (e.g. <code class="docutils literal notranslate"><span class="pre">cxx_std_11</span></code>) that requires use of a compiler mode
that is at minimum aware of that standard, but could be greater.
This is simpler than specifying all the features individually, but does
not guarantee the existence of any particular feature.
Diagnosis of use of unsupported features will be delayed until compile time.</p>
<p>For example, if C++ 11 features are used extensively in a project's
header files, then clients must use a compiler mode that is no less
than C++ 11.  This can be requested with the code:</p>
<div class="highlight-cmake notranslate"><div class="highlight"><pre><span></span><span class="nf">target_compile_features(</span><span class="nb">mylib</span><span class="w"> </span><span class="no">PUBLIC</span><span class="w"> </span><span class="nb">cxx_std_11</span><span class="nf">)</span>
</pre></div>
</div>
<p>In this example, CMake will ensure the compiler is invoked in a mode
of at-least C++ 11 (or C++ 14, C++ 17, ...), adding flags such as
<code class="docutils literal notranslate"><span class="pre">-std=gnu++11</span></code> if necessary.  This applies to sources within <code class="docutils literal notranslate"><span class="pre">mylib</span></code>
as well as any dependents (that may include headers from <code class="docutils literal notranslate"><span class="pre">mylib</span></code>).</p>
<div class="admonition note">
<p class="admonition-title">Note</p>
<p>If the compiler's default standard level is at least that
of the requested feature, CMake may omit the <code class="docutils literal notranslate"><span class="pre">-std=</span></code> flag.
The flag may still be added if the compiler's default extensions mode
does not match the <span class="target" id="index-0-prop_tgt:&lt;LANG&gt;_EXTENSIONS"></span><a class="reference internal" href="../prop_tgt/LANG_EXTENSIONS.html#prop_tgt:&lt;LANG&gt;_EXTENSIONS" title="&lt;LANG&gt;_EXTENSIONS"><code class="xref cmake cmake-prop_tgt docutils literal notranslate"><span class="pre">&lt;LANG&gt;_EXTENSIONS</span></code></a> target property,
or if the <span class="target" id="index-0-prop_tgt:&lt;LANG&gt;_STANDARD"></span><a class="reference internal" href="../prop_tgt/LANG_STANDARD.html#prop_tgt:&lt;LANG&gt;_STANDARD" title="&lt;LANG&gt;_STANDARD"><code class="xref cmake cmake-prop_tgt docutils literal notranslate"><span class="pre">&lt;LANG&gt;_STANDARD</span></code></a> target property is set.</p>
</div>
</section>
<section id="availability-of-compiler-extensions">
<h3><a class="toc-backref" href="#id7" role="doc-backlink">Availability of Compiler Extensions</a><a class="headerlink" href="#availability-of-compiler-extensions" title="Link to this heading">¶</a></h3>
<p>The <span class="target" id="index-1-prop_tgt:&lt;LANG&gt;_EXTENSIONS"></span><a class="reference internal" href="../prop_tgt/LANG_EXTENSIONS.html#prop_tgt:&lt;LANG&gt;_EXTENSIONS" title="&lt;LANG&gt;_EXTENSIONS"><code class="xref cmake cmake-prop_tgt docutils literal notranslate"><span class="pre">&lt;LANG&gt;_EXTENSIONS</span></code></a> target property defaults to the compiler's
default (see <span class="target" id="index-0-variable:CMAKE_&lt;LANG&gt;_EXTENSIONS_DEFAULT"></span><a class="reference internal" href="../variable/CMAKE_LANG_EXTENSIONS_DEFAULT.html#variable:CMAKE_&lt;LANG&gt;_EXTENSIONS_DEFAULT" title="CMAKE_&lt;LANG&gt;_EXTENSIONS_DEFAULT"><code class="xref cmake cmake-variable docutils literal notranslate"><span class="pre">CMAKE_&lt;LANG&gt;_EXTENSIONS_DEFAULT</span></code></a>). Note that because
most compilers enable extensions by default, this may expose portability bugs
in user code or in the headers of third-party dependencies.</p>
<p><span class="target" id="index-2-prop_tgt:&lt;LANG&gt;_EXTENSIONS"></span><a class="reference internal" href="../prop_tgt/LANG_EXTENSIONS.html#prop_tgt:&lt;LANG&gt;_EXTENSIONS" title="&lt;LANG&gt;_EXTENSIONS"><code class="xref cmake cmake-prop_tgt docutils literal notranslate"><span class="pre">&lt;LANG&gt;_EXTENSIONS</span></code></a> used to default to <code class="docutils literal notranslate"><span class="pre">ON</span></code>. See <span class="target" id="index-0-policy:CMP0128"></span><a class="reference internal" href="../policy/CMP0128.html#policy:CMP0128" title="CMP0128"><code class="xref cmake cmake-policy docutils literal notranslate"><span class="pre">CMP0128</span></code></a>.</p>
</section>
</section>
<section id="optional-compile-features">
<h2><a class="toc-backref" href="#id8" role="doc-backlink">Optional Compile Features</a><a class="headerlink" href="#optional-compile-features" title="Link to this heading">¶</a></h2>
<p>Compile features may be preferred if available, without creating a hard
requirement.   This can be achieved by <em>not</em> specifying features with
<span class="target" id="index-2-command:target_compile_features"></span><a class="reference internal" href="../command/target_compile_features.html#command:target_compile_features" title="target_compile_features"><code class="xref cmake cmake-command docutils literal notranslate"><span class="pre">target_compile_features()</span></code></a> and instead checking the compiler
capabilities with preprocessor conditions in project code.</p>
<p>In this use-case, the project may wish to establish a particular language
standard if available from the compiler, and use preprocessor conditions
to detect the features actually available.  A language standard may be
established by <a class="reference internal" href="#requiring-language-standards">Requiring Language Standards</a> using
<span class="target" id="index-3-command:target_compile_features"></span><a class="reference internal" href="../command/target_compile_features.html#command:target_compile_features" title="target_compile_features"><code class="xref cmake cmake-command docutils literal notranslate"><span class="pre">target_compile_features()</span></code></a> with meta-features like <code class="docutils literal notranslate"><span class="pre">cxx_std_11</span></code>,
or by setting the <span class="target" id="index-0-prop_tgt:CXX_STANDARD"></span><a class="reference internal" href="../prop_tgt/CXX_STANDARD.html#prop_tgt:CXX_STANDARD" title="CXX_STANDARD"><code class="xref cmake cmake-prop_tgt docutils literal notranslate"><span class="pre">CXX_STANDARD</span></code></a> target property or
<span class="target" id="index-0-variable:CMAKE_CXX_STANDARD"></span><a class="reference internal" href="../variable/CMAKE_CXX_STANDARD.html#variable:CMAKE_CXX_STANDARD" title="CMAKE_CXX_STANDARD"><code class="xref cmake cmake-variable docutils literal notranslate"><span class="pre">CMAKE_CXX_STANDARD</span></code></a> variable.</p>
<p>See also policy <span class="target" id="index-0-policy:CMP0120"></span><a class="reference internal" href="../policy/CMP0120.html#policy:CMP0120" title="CMP0120"><code class="xref cmake cmake-policy docutils literal notranslate"><span class="pre">CMP0120</span></code></a> and legacy documentation on
<a class="reference internal" href="../module/WriteCompilerDetectionHeader.html#wcdh-example-usage"><span class="std std-ref">Example Usage</span></a> of the deprecated
<span class="target" id="index-0-module:WriteCompilerDetectionHeader"></span><a class="reference internal" href="../module/WriteCompilerDetectionHeader.html#module:WriteCompilerDetectionHeader" title="WriteCompilerDetectionHeader"><code class="xref cmake cmake-module docutils literal notranslate"><span class="pre">WriteCompilerDetectionHeader</span></code></a> module.</p>
</section>
<section id="conditional-compilation-options">
<h2><a class="toc-backref" href="#id9" role="doc-backlink">Conditional Compilation Options</a><a class="headerlink" href="#conditional-compilation-options" title="Link to this heading">¶</a></h2>
<p>Libraries may provide entirely different header files depending on
requested compiler features.</p>
<p>For example, a header at <code class="docutils literal notranslate"><span class="pre">with_variadics/interface.h</span></code> may contain:</p>
<div class="highlight-c++ notranslate"><div class="highlight"><pre><span></span><span class="k">template</span><span class="o">&lt;</span><span class="kt">int</span><span class="w"> </span><span class="n">I</span><span class="p">,</span><span class="w"> </span><span class="kt">int</span><span class="p">...</span><span class="w"> </span><span class="n">Is</span><span class="o">&gt;</span>
<span class="k">struct</span><span class="w"> </span><span class="nc">Interface</span><span class="p">;</span>

<span class="k">template</span><span class="o">&lt;</span><span class="kt">int</span><span class="w"> </span><span class="n">I</span><span class="o">&gt;</span>
<span class="k">struct</span><span class="w"> </span><span class="nc">Interface</span><span class="o">&lt;</span><span class="n">I</span><span class="o">&gt;</span>
<span class="p">{</span>
<span class="w">  </span><span class="k">static</span><span class="w"> </span><span class="kt">int</span><span class="w"> </span><span class="nf">accumulate</span><span class="p">()</span>
<span class="w">  </span><span class="p">{</span>
<span class="w">    </span><span class="k">return</span><span class="w"> </span><span class="n">I</span><span class="p">;</span>
<span class="w">  </span><span class="p">}</span>
<span class="p">};</span>

<span class="k">template</span><span class="o">&lt;</span><span class="kt">int</span><span class="w"> </span><span class="n">I</span><span class="p">,</span><span class="w"> </span><span class="kt">int</span><span class="p">...</span><span class="w"> </span><span class="n">Is</span><span class="o">&gt;</span>
<span class="k">struct</span><span class="w"> </span><span class="nc">Interface</span>
<span class="p">{</span>
<span class="w">  </span><span class="k">static</span><span class="w"> </span><span class="kt">int</span><span class="w"> </span><span class="nf">accumulate</span><span class="p">()</span>
<span class="w">  </span><span class="p">{</span>
<span class="w">    </span><span class="k">return</span><span class="w"> </span><span class="n">I</span><span class="w"> </span><span class="o">+</span><span class="w"> </span><span class="n">Interface</span><span class="o">&lt;</span><span class="n">Is</span><span class="p">...</span><span class="o">&gt;::</span><span class="n">accumulate</span><span class="p">();</span>
<span class="w">  </span><span class="p">}</span>
<span class="p">};</span>
</pre></div>
</div>
<p>while a header at <code class="docutils literal notranslate"><span class="pre">no_variadics/interface.h</span></code> may contain:</p>
<div class="highlight-c++ notranslate"><div class="highlight"><pre><span></span><span class="k">template</span><span class="o">&lt;</span><span class="kt">int</span><span class="w"> </span><span class="n">I1</span><span class="p">,</span><span class="w"> </span><span class="kt">int</span><span class="w"> </span><span class="n">I2</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="mi">0</span><span class="p">,</span><span class="w"> </span><span class="kt">int</span><span class="w"> </span><span class="n">I3</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="mi">0</span><span class="p">,</span><span class="w"> </span><span class="kt">int</span><span class="w"> </span><span class="n">I4</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="mi">0</span><span class="o">&gt;</span>
<span class="k">struct</span><span class="w"> </span><span class="nc">Interface</span>
<span class="p">{</span>
<span class="w">  </span><span class="k">static</span><span class="w"> </span><span class="kt">int</span><span class="w"> </span><span class="nf">accumulate</span><span class="p">()</span><span class="w"> </span><span class="p">{</span><span class="w"> </span><span class="k">return</span><span class="w"> </span><span class="n">I1</span><span class="w"> </span><span class="o">+</span><span class="w"> </span><span class="n">I2</span><span class="w"> </span><span class="o">+</span><span class="w"> </span><span class="n">I3</span><span class="w"> </span><span class="o">+</span><span class="w"> </span><span class="n">I4</span><span class="p">;</span><span class="w"> </span><span class="p">}</span>
<span class="p">};</span>
</pre></div>
</div>
<p>It may be possible to write an abstraction <code class="docutils literal notranslate"><span class="pre">interface.h</span></code> header
containing something like:</p>
<div class="highlight-c++ notranslate"><div class="highlight"><pre><span></span><span class="cp">#ifdef HAVE_CXX_VARIADIC_TEMPLATES</span>
<span class="cp">#include</span><span class="w"> </span><span class="cpf">&quot;with_variadics/interface.h&quot;</span>
<span class="cp">#else</span>
<span class="cp">#include</span><span class="w"> </span><span class="cpf">&quot;no_variadics/interface.h&quot;</span>
<span class="cp">#endif</span>
</pre></div>
</div>
<p>However this could be unmaintainable if there are many files to
abstract. What is needed is to use alternative include directories
depending on the compiler capabilities.</p>
<p>CMake provides a <code class="docutils literal notranslate"><span class="pre">COMPILE_FEATURES</span></code>
<span class="target" id="index-0-manual:cmake-generator-expressions(7)"></span><a class="reference internal" href="cmake-generator-expressions.7.html#manual:cmake-generator-expressions(7)" title="cmake-generator-expressions(7)"><code class="xref cmake cmake-manual docutils literal notranslate"><span class="pre">generator</span> <span class="pre">expression</span></code></a> to implement
such conditions.  This may be used with the build-property commands such as
<span class="target" id="index-0-command:target_include_directories"></span><a class="reference internal" href="../command/target_include_directories.html#command:target_include_directories" title="target_include_directories"><code class="xref cmake cmake-command docutils literal notranslate"><span class="pre">target_include_directories()</span></code></a> and <span class="target" id="index-0-command:target_link_libraries"></span><a class="reference internal" href="../command/target_link_libraries.html#command:target_link_libraries" title="target_link_libraries"><code class="xref cmake cmake-command docutils literal notranslate"><span class="pre">target_link_libraries()</span></code></a>
to set the appropriate <span class="target" id="index-1-manual:cmake-buildsystem(7)"></span><a class="reference internal" href="cmake-buildsystem.7.html#manual:cmake-buildsystem(7)" title="cmake-buildsystem(7)"><code class="xref cmake cmake-manual docutils literal notranslate"><span class="pre">buildsystem</span></code></a>
properties:</p>
<div class="highlight-cmake notranslate"><div class="highlight"><pre><span></span><span class="nf">add_library(</span><span class="nb">foo</span><span class="w"> </span><span class="no">INTERFACE</span><span class="nf">)</span>
<span class="nf">set(</span><span class="nb">with_variadics</span><span class="w"> </span><span class="o">${</span><span class="nt">CMAKE_CURRENT_SOURCE_DIR</span><span class="o">}</span><span class="na">/with_variadics</span><span class="nf">)</span>
<span class="nf">set(</span><span class="nb">no_variadics</span><span class="w"> </span><span class="o">${</span><span class="nt">CMAKE_CURRENT_SOURCE_DIR</span><span class="o">}</span><span class="na">/no_variadics</span><span class="nf">)</span>
<span class="nf">target_include_directories(</span><span class="nb">foo</span>
<span class="w">  </span><span class="no">INTERFACE</span>
<span class="w">    </span><span class="s">&quot;$&lt;$&lt;COMPILE_FEATURES:cxx_variadic_templates&gt;:${with_variadics}&gt;&quot;</span>
<span class="w">    </span><span class="s">&quot;$&lt;$&lt;NOT:$&lt;COMPILE_FEATURES:cxx_variadic_templates&gt;&gt;:${no_variadics}&gt;&quot;</span>
<span class="w">  </span><span class="nf">)</span>
</pre></div>
</div>
<p>Consuming code then simply links to the <code class="docutils literal notranslate"><span class="pre">foo</span></code> target as usual and uses
the feature-appropriate include directory</p>
<div class="highlight-cmake notranslate"><div class="highlight"><pre><span></span><span class="nf">add_executable(</span><span class="nb">consumer_with</span><span class="w"> </span><span class="nb">consumer_with.cpp</span><span class="nf">)</span>
<span class="nf">target_link_libraries(</span><span class="nb">consumer_with</span><span class="w"> </span><span class="nb">foo</span><span class="nf">)</span>
<span class="nf">set_property(</span><span class="no">TARGET</span><span class="w"> </span><span class="nb">consumer_with</span><span class="w"> </span><span class="no">CXX_STANDARD</span><span class="w"> </span><span class="m">11</span><span class="nf">)</span>

<span class="nf">add_executable(</span><span class="nb">consumer_no</span><span class="w"> </span><span class="nb">consumer_no.cpp</span><span class="nf">)</span>
<span class="nf">target_link_libraries(</span><span class="nb">consumer_no</span><span class="w"> </span><span class="nb">foo</span><span class="nf">)</span>
</pre></div>
</div>
</section>
<section id="supported-compilers">
<h2><a class="toc-backref" href="#id10" role="doc-backlink">Supported Compilers</a><a class="headerlink" href="#supported-compilers" title="Link to this heading">¶</a></h2>
<p>CMake is currently aware of the <span class="target" id="index-1-prop_tgt:CXX_STANDARD"></span><a class="reference internal" href="../prop_tgt/CXX_STANDARD.html#prop_tgt:CXX_STANDARD" title="CXX_STANDARD"><code class="xref cmake cmake-prop_tgt docutils literal notranslate"><span class="pre">C++</span> <span class="pre">standards</span></code></a>
and <span class="target" id="index-2-prop_gbl:CMAKE_CXX_KNOWN_FEATURES"></span><a class="reference internal" href="../prop_gbl/CMAKE_CXX_KNOWN_FEATURES.html#prop_gbl:CMAKE_CXX_KNOWN_FEATURES" title="CMAKE_CXX_KNOWN_FEATURES"><code class="xref cmake cmake-prop_gbl docutils literal notranslate"><span class="pre">compile</span> <span class="pre">features</span></code></a> available from
the following <span class="target" id="index-0-variable:CMAKE_&lt;LANG&gt;_COMPILER_ID"></span><a class="reference internal" href="../variable/CMAKE_LANG_COMPILER_ID.html#variable:CMAKE_&lt;LANG&gt;_COMPILER_ID" title="CMAKE_&lt;LANG&gt;_COMPILER_ID"><code class="xref cmake cmake-variable docutils literal notranslate"><span class="pre">compiler</span> <span class="pre">ids</span></code></a> as of the
versions specified for each:</p>
<ul class="simple">
<li><p><code class="docutils literal notranslate"><span class="pre">AppleClang</span></code>: Apple Clang for Xcode versions 4.4+.</p></li>
<li><p><code class="docutils literal notranslate"><span class="pre">Clang</span></code>: Clang compiler versions 2.9+.</p></li>
<li><p><code class="docutils literal notranslate"><span class="pre">GNU</span></code>: GNU compiler versions 4.4+.</p></li>
<li><p><code class="docutils literal notranslate"><span class="pre">MSVC</span></code>: Microsoft Visual Studio versions 2010+.</p></li>
<li><p><code class="docutils literal notranslate"><span class="pre">SunPro</span></code>: Oracle SolarisStudio versions 12.4+.</p></li>
<li><p><code class="docutils literal notranslate"><span class="pre">Intel</span></code>: Intel compiler versions 12.1+.</p></li>
</ul>
<p>CMake is currently aware of the <span class="target" id="index-0-prop_tgt:C_STANDARD"></span><a class="reference internal" href="../prop_tgt/C_STANDARD.html#prop_tgt:C_STANDARD" title="C_STANDARD"><code class="xref cmake cmake-prop_tgt docutils literal notranslate"><span class="pre">C</span> <span class="pre">standards</span></code></a>
and <span class="target" id="index-1-prop_gbl:CMAKE_C_KNOWN_FEATURES"></span><a class="reference internal" href="../prop_gbl/CMAKE_C_KNOWN_FEATURES.html#prop_gbl:CMAKE_C_KNOWN_FEATURES" title="CMAKE_C_KNOWN_FEATURES"><code class="xref cmake cmake-prop_gbl docutils literal notranslate"><span class="pre">compile</span> <span class="pre">features</span></code></a> available from
the following <span class="target" id="index-1-variable:CMAKE_&lt;LANG&gt;_COMPILER_ID"></span><a class="reference internal" href="../variable/CMAKE_LANG_COMPILER_ID.html#variable:CMAKE_&lt;LANG&gt;_COMPILER_ID" title="CMAKE_&lt;LANG&gt;_COMPILER_ID"><code class="xref cmake cmake-variable docutils literal notranslate"><span class="pre">compiler</span> <span class="pre">ids</span></code></a> as of the
versions specified for each:</p>
<ul class="simple">
<li><p>all compilers and versions listed above for C++.</p></li>
<li><p><code class="docutils literal notranslate"><span class="pre">GNU</span></code>: GNU compiler versions 3.4+</p></li>
</ul>
<p>CMake is currently aware of the <span class="target" id="index-2-prop_tgt:CXX_STANDARD"></span><a class="reference internal" href="../prop_tgt/CXX_STANDARD.html#prop_tgt:CXX_STANDARD" title="CXX_STANDARD"><code class="xref cmake cmake-prop_tgt docutils literal notranslate"><span class="pre">C++</span> <span class="pre">standards</span></code></a> and
their associated meta-features (e.g. <code class="docutils literal notranslate"><span class="pre">cxx_std_11</span></code>) available from the
following <span class="target" id="index-2-variable:CMAKE_&lt;LANG&gt;_COMPILER_ID"></span><a class="reference internal" href="../variable/CMAKE_LANG_COMPILER_ID.html#variable:CMAKE_&lt;LANG&gt;_COMPILER_ID" title="CMAKE_&lt;LANG&gt;_COMPILER_ID"><code class="xref cmake cmake-variable docutils literal notranslate"><span class="pre">compiler</span> <span class="pre">ids</span></code></a> as of the
versions specified for each:</p>
<ul class="simple">
<li><p><code class="docutils literal notranslate"><span class="pre">Cray</span></code>: Cray Compiler Environment version 8.1+.</p></li>
<li><p><code class="docutils literal notranslate"><span class="pre">Fujitsu</span></code>: Fujitsu HPC compiler 4.0+.</p></li>
<li><p><code class="docutils literal notranslate"><span class="pre">PGI</span></code>: PGI version 12.10+.</p></li>
<li><p><code class="docutils literal notranslate"><span class="pre">NVHPC</span></code>: NVIDIA HPC compilers version 11.0+.</p></li>
<li><p><code class="docutils literal notranslate"><span class="pre">TI</span></code>: Texas Instruments compiler.</p></li>
<li><p><code class="docutils literal notranslate"><span class="pre">TIClang</span></code>: Texas Instruments Clang-based compilers.</p></li>
<li><p><code class="docutils literal notranslate"><span class="pre">XL</span></code>: IBM XL version 10.1+.</p></li>
</ul>
<p>CMake is currently aware of the <span class="target" id="index-1-prop_tgt:C_STANDARD"></span><a class="reference internal" href="../prop_tgt/C_STANDARD.html#prop_tgt:C_STANDARD" title="C_STANDARD"><code class="xref cmake cmake-prop_tgt docutils literal notranslate"><span class="pre">C</span> <span class="pre">standards</span></code></a> and
their associated meta-features (e.g. <code class="docutils literal notranslate"><span class="pre">c_std_99</span></code>) available from the
following <span class="target" id="index-3-variable:CMAKE_&lt;LANG&gt;_COMPILER_ID"></span><a class="reference internal" href="../variable/CMAKE_LANG_COMPILER_ID.html#variable:CMAKE_&lt;LANG&gt;_COMPILER_ID" title="CMAKE_&lt;LANG&gt;_COMPILER_ID"><code class="xref cmake cmake-variable docutils literal notranslate"><span class="pre">compiler</span> <span class="pre">ids</span></code></a> as of the
versions specified for each:</p>
<ul class="simple">
<li><p>all compilers and versions listed above with only meta-features for C++.</p></li>
</ul>
<p>CMake is currently aware of the <span class="target" id="index-0-prop_tgt:CUDA_STANDARD"></span><a class="reference internal" href="../prop_tgt/CUDA_STANDARD.html#prop_tgt:CUDA_STANDARD" title="CUDA_STANDARD"><code class="xref cmake cmake-prop_tgt docutils literal notranslate"><span class="pre">CUDA</span> <span class="pre">standards</span></code></a> and
their associated meta-features (e.g. <code class="docutils literal notranslate"><span class="pre">cuda_std_11</span></code>) available from the
following <span class="target" id="index-4-variable:CMAKE_&lt;LANG&gt;_COMPILER_ID"></span><a class="reference internal" href="../variable/CMAKE_LANG_COMPILER_ID.html#variable:CMAKE_&lt;LANG&gt;_COMPILER_ID" title="CMAKE_&lt;LANG&gt;_COMPILER_ID"><code class="xref cmake cmake-variable docutils literal notranslate"><span class="pre">compiler</span> <span class="pre">ids</span></code></a> as of the
versions specified for each:</p>
<ul class="simple">
<li><p><code class="docutils literal notranslate"><span class="pre">Clang</span></code>: Clang compiler 5.0+.</p></li>
<li><p><code class="docutils literal notranslate"><span class="pre">NVIDIA</span></code>: NVIDIA nvcc compiler 7.5+.</p></li>
</ul>
</section>
<section id="language-standard-flags">
<span id="id2"></span><h2><a class="toc-backref" href="#id11" role="doc-backlink">Language Standard Flags</a><a class="headerlink" href="#language-standard-flags" title="Link to this heading">¶</a></h2>
<p>In order to satisfy requirements specified by the
<span class="target" id="index-4-command:target_compile_features"></span><a class="reference internal" href="../command/target_compile_features.html#command:target_compile_features" title="target_compile_features"><code class="xref cmake cmake-command docutils literal notranslate"><span class="pre">target_compile_features()</span></code></a> command or the
<span class="target" id="index-0-variable:CMAKE_&lt;LANG&gt;_STANDARD"></span><a class="reference internal" href="../variable/CMAKE_LANG_STANDARD.html#variable:CMAKE_&lt;LANG&gt;_STANDARD" title="CMAKE_&lt;LANG&gt;_STANDARD"><code class="xref cmake cmake-variable docutils literal notranslate"><span class="pre">CMAKE_&lt;LANG&gt;_STANDARD</span></code></a> variable, CMake may pass a
language standard flag to the compiler, such as <code class="docutils literal notranslate"><span class="pre">-std=c++11</span></code>.</p>
<p>For <a class="reference internal" href="cmake-generators.7.html#visual-studio-generators"><span class="std std-ref">Visual Studio Generators</span></a>, CMake cannot precisely control
the placement of the language standard flag on the compiler command line.
For <a class="reference internal" href="cmake-generators.7.html#ninja-generators"><span class="std std-ref">Ninja Generators</span></a>, <a class="reference internal" href="cmake-generators.7.html#makefile-generators"><span class="std std-ref">Makefile Generators</span></a>, and
<span class="target" id="index-0-generator:Xcode"></span><a class="reference internal" href="../generator/Xcode.html#generator:Xcode" title="Xcode"><code class="xref cmake cmake-generator docutils literal notranslate"><span class="pre">Xcode</span></code></a>, CMake places the language standard flag just after
the language-wide flags from <span class="target" id="index-0-variable:CMAKE_&lt;LANG&gt;_FLAGS"></span><a class="reference internal" href="../variable/CMAKE_LANG_FLAGS.html#variable:CMAKE_&lt;LANG&gt;_FLAGS" title="CMAKE_&lt;LANG&gt;_FLAGS"><code class="xref cmake cmake-variable docutils literal notranslate"><span class="pre">CMAKE_&lt;LANG&gt;_FLAGS</span></code></a>
and <span class="target" id="index-0-variable:CMAKE_&lt;LANG&gt;_FLAGS_&lt;CONFIG&gt;"></span><a class="reference internal" href="../variable/CMAKE_LANG_FLAGS_CONFIG.html#variable:CMAKE_&lt;LANG&gt;_FLAGS_&lt;CONFIG&gt;" title="CMAKE_&lt;LANG&gt;_FLAGS_&lt;CONFIG&gt;"><code class="xref cmake cmake-variable docutils literal notranslate"><span class="pre">CMAKE_&lt;LANG&gt;_FLAGS_&lt;CONFIG&gt;</span></code></a>.</p>
<div class="versionchanged">
<p><span class="versionmodified changed">Changed in version 3.26: </span>The language standard flag is placed before flags specified by other
abstractions such as the <span class="target" id="index-0-command:target_compile_options"></span><a class="reference internal" href="../command/target_compile_options.html#command:target_compile_options" title="target_compile_options"><code class="xref cmake cmake-command docutils literal notranslate"><span class="pre">target_compile_options()</span></code></a> command.
Prior to CMake 3.26, the language standard flag was placed after them.</p>
</div>
</section>
</section>


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    <h3>Table of Contents</h3>
    <ul>
<li><a class="reference internal" href="#">cmake-compile-features(7)</a><ul>
<li><a class="reference internal" href="#introduction">Introduction</a></li>
<li><a class="reference internal" href="#compile-feature-requirements">Compile Feature Requirements</a><ul>
<li><a class="reference internal" href="#requiring-language-standards">Requiring Language Standards</a></li>
<li><a class="reference internal" href="#availability-of-compiler-extensions">Availability of Compiler Extensions</a></li>
</ul>
</li>
<li><a class="reference internal" href="#optional-compile-features">Optional Compile Features</a></li>
<li><a class="reference internal" href="#conditional-compilation-options">Conditional Compilation Options</a></li>
<li><a class="reference internal" href="#supported-compilers">Supported Compilers</a></li>
<li><a class="reference internal" href="#language-standard-flags">Language Standard Flags</a></li>
</ul>
</li>
</ul>

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